The Supreme Court on Tuesday struck down a key part of the Voting Rights Act of 1965 — the map that determines which states must get federal permission before they change their voting laws. The ruling, a 5-4 decision by Chief Justice John Roberts, leaves the future of the law deeply uncertain because it will be up to a sharply divided Congress to redraw the map. “Our country has changed, and while any racial discrimination in voting is too much, Congress must ensure that the legislation it passes to remedy that problem speaks to current conditions,” Roberts wrote for the court. Under the law, nine mostly Southern states must get permission from the Justice Department or a special panel of three federal judges before they make changes. The rule also applies to 12 cities and 57 counties elsewhere. The act is considered the most important piece of civil rights legislation ever passed. Congress has renewed it four times, most recently in 2006, with overwhelming margins in both houses. That renewal extended the law through 2031. But the law still uses election data from 1972 to determine which states, cities and counties are covered. Some jurisdictions complained that they are being punished for the sins of many decades ago.

Congress' most recent renewal of the full law really was overwhelming; it received nearly 400 votes in the House, and was re-upped 98-0 in the Senate. Both chambers were controlled by Republicans at the time. But questions that may be untouchable for the political class aren't immune from the Court's scrutiny. Four conservative justices and swing vote Anthony Kennedy determined that some of the VRA's heavy-handed protections that were necessary nearly five decades ago no longer apply. Here's a portion of the majority opinion, in which Chief Justice Roberts -- writing for the Court -- notes that history didn't end in the mid-1960's. Times change, he argues, and so should onerous racial provisions that have outlived their relevancy:

The Voting Rights Act of 1965 employed extraordinary measures to address an extraordinary problem. Section 5 of the Act required States to obtain federal permission before enacting any law related to voting—a drastic departure from basic principles of federalism. And §4 of the Act applied that requirement only to some States—an equally dramatic departure from the principle that all States enjoy equal sovereignty. This was strong medicine, but Congress determined it was needed to address entrenched racial discrimination in voting, “an insidious and pervasive evil which had been perpetuated in certain parts of our country through unremitting and ingenious defiance of the Constitution.” ... The Government has a fallback argument—because the formula was relevant in 1965, its continued use is permissible so long as any discrimination remains in the States identified in 1965. But this does not look to “current political conditions,” Northwest Austin, supra, at 203, instead relying on a comparison between the States in 1965. But history did not end in 1965. In assessing the “current need[ ]” for a preclearance system treating States differently from one another today, history since 1965 cannot be ignored. The Fifteenth Amendment is not designed to punish for the past; its purpose is to ensure a better future. To serve that purpose, Congress—if it is to divide the States—must identify those jurisdictions to be singled out on a basis that makes sense in light of current conditions...

The justices relied on recent data indicating that the rank inequality and codified bigotry that existed in 1965 have since been remedied: "As part of the ruling, the court published a chart comparing white and black voter registration in 1965 and in 2004 in the six states originally covered by the law. In Alabama, for example, the white registration rate was 69 percent and the black rate 19 percent in 1965. By 2004, that gap had all but disappeared — 74 percent for whites and 73 percent for blacks." Section four of the law -- which determined which specific states and jurisdictions were subject to the 'advanced permission' federal regulations -- was tossed out. Section five, which permits such regulations in the first place, remains intact. The immediate consequences of those outcomes, via ABC News:

The court left standing Section 5 of the law, a key section that requires states with a history of voter discrimination to have any changes to voting rules approved by federal officials, but strikes down the coverage formula used to choose which states should be covered. "We issue no holding on section 5 itself, only on the coverage formula. Congress may draft another formula based on current conditions," Roberts said. Supporters of the law fear that Congress—with its deepening partisan divide-- will not act.

National Journal's Reid Wilson makes an interesting observation that hints at the contemporary practical implications of today's ruling:

Prior to its fall, Section four of the VRA also applied to certain jurisdictions in places like New York City and New Hampshire. Here is one egregious example of section four of the VRA being exploited by Eric Holder's Justice Department to benefit the Democratic Party in 2009. The DOJ intervened to protect the citizens of (overwhelmingly African-American) Kinston, North Carolina from themselves.